The incident occurred on May 3, 2021, at about 10:30 pm (local time) near Mexico City's Olivos station on a recently constructed subway line. The subway system of Mexico City is one of the busiest in North America with only that of New York's carrying more passengers daily. During 2019, the system carried more than 1.65 billion passengers.
The structure suddenly collapsed as a train was passing over it and impacted a roadway below causing severe damage, injuring more than 70 people and killing at least 24. A victim that survived stated that many people went flying and impacted with the train's ceiling once the bridge gave way.
The train remained partially hanging over the road (at a V-shape) with many victims being trapped into the carriages. People gathered around the debris with many friends and relatives of those trapped arriving at the site. According to witnesses, one passenger managed to break a window enabling others to escape.
Officials initiated a rescue operation through the night with many injured being hospitalized. The operation was halted after a crane was sent to the scene to stabilize the hanging carriages due to fears of potential collapse into the road below.
A thorough investigation on the causes of the collapse will soon be launched. Florencia Serrania, Mexico City Metro Director stated: "I consider that I will collaborate with the attorney general to know what was the cause of this structural failure, and I think that's what we all want, get to the bottom of this".
Authorities will employ an international company specialized in subway incidents as an external investigator. Marcelo Ebrard, Mexico's foreign minister, said that that was "the most terrible accident we've ever had in the public transport system". Sheinbaum Claudia, the major of Mexico City stated that the line was being monitoring and maintained daily and that the truth on the causes of the collapse must be found.
The subway line is the newest line of the system that opened 9 years ago after 4 years of construction. However, there has been some criticism on its design and construction before the current incident. In particular, there were concerns about casual construction procedures, irregularities and cost overruns. 11 out of 20 stations of the line were closed in 2014-2015 for repair works while 4 stations were also shut in 2017 after a powerful earthquake struck Mexico City. In fact, people reported observing cracks in the bridge that collapsed after the aforementioned earthquake.
More accidents have been documented in Mexico City's subway. In March 2020, 2 trains crashed at the Tacubaya station resulting in 1 fatality and 41 injuries. 5 years earlier, another train collision in Oceania station caused 12 injuries.